Subsequent Events - Additional Information (Detail) (USD $)	1 Months Ended		9 Months Ended		1 Months Ended	9 Months Ended		1 Months Ended	9 Months Ended			1 Months Ended
	Oct. 31, 2011 Common Stock	Apr. 30, 2013 Macquarie Capital Incorporated At Market Sales Agreement	Sep. 30, 2013 Macquarie Capital Incorporated At Market Sales Agreement	Apr. 17, 2013 Macquarie Capital Incorporated At Market Sales Agreement	Apr. 30, 2013 Macquarie Capital Incorporated At Market Sales Agreement Minimum	Sep. 30, 2013 Macquarie Capital Incorporated At Market Sales Agreement Minimum	Sep. 30, 2013 Macquarie Capital Incorporated At Market Sales Agreement Maximum	Aug. 31, 2012 Aspire Capital Fund Llc Common Stock Kissei Stock Purchase Agreement	Sep. 30, 2013 Aspire Capital Fund Llc Common Stock Kissei Stock Purchase Agreement	Sep. 30, 2013 Aspire Capital Fund Llc Common Stock Kissei Stock Purchase Agreement Minimum	Sep. 30, 2013 Aspire Capital Fund Llc Common Stock Kissei Stock Purchase Agreement Maximum	Nov. 05, 2013 Subsequent Event Macquarie Capital Incorporated At Market Sales Agreement	Oct. 16, 2013 Subsequent Event Macquarie Capital Incorporated At Market Sales Agreement	Nov. 05, 2013 Subsequent Event Macquarie Capital Incorporated At Market Sales Agreement Minimum	Oct. 16, 2013 Subsequent Event Macquarie Capital Incorporated At Market Sales Agreement Minimum	Nov. 05, 2013 Subsequent Event Macquarie Capital Incorporated At Market Sales Agreement Maximum
Subsequent Event [Line Items]
Stock purchase agreement, aggregate amount of common stock agreed to be purchased				$ 6,000,000				$ 20,000,000					$ 10,000,000
Stock Purchase Agreement, maximum amount of sale		50,000											50,000
Stock Purchase Agreement, maximum amount of sale terms		10% of the lower of the 5-day or 3-month average daily traded value of our common stock											10% of the lower of the 5-day or 3-month average daily traded value of our common stock
Shares purchase & equity issuance, per share amount	$ 2.50				$ 1.19	$ 2.44	$ 4.10			$ 1.60	$ 3.82			$ 2.52	$ 1.29	$ 2.58
Sales commission as a percentage of gross proceeds		8.00%											7.00%
Common Stock purchase agreement, gross proceeds from sale			6,000,000									51,000
Common Stock purchase agreement, net proceeds from sale			$ 5,500,000									$ 47,400
Common Stock purchase agreement, number shares sold	800,000		1,936,237					363,636	2,504,532			20,000
Agreement Termination Date									October 17, 2013